The present invention relates to locks for windows and, more specifically, to a single point lock operator used in conjunction with a keeper to lock a casement window.
An inexpensive means for locking a casement window is provided by a cam lock or a single point lock. Existing cam or single point locks have a locking lever or hook with an elongated body that engages a keeper at one end and a handle at the other end. Upon rotation of the handle from inside the window, the lever rotates and engages the keeper to lock the window. A housing is normally provided which covers the hole in the frame through which the connection between the handle and the lever passes.
One particular problem with single point locks of the above-described type is the inability of these locks to provide an effective seal against the inside surface of the window frame. Specifically, the typical single point lock includes an integrally connected handle/lever which passes through a housing mounted to the inside surface of the frame. Because the construction of the handle and lever must be sturdy, the hole in the housing through which the handle/lever passes is of a substantial size. Accordingly, providing a seal for this large hole is problematic. One solution to this sealing problem is provided in U.S. Pat. No. 4,674,777 which provides a specially designed seal to fit around the rectangularly shaped hole through which the handle/lever passes. The seal provided in the '777 patent is problematic because in addition to being specially designed, it is also difficult to install. Therefore, manufacturing costs are substantial.
Further, after an extended period of use, a certain amount of play may develop between the lock and the keeper when a single point lock is in a closed position. As a result of this loose fit or play, the lock may tend to rattle or vibrate during windy conditions. Further, any looseness in the engagement between the lever and the keeper makes the lock susceptible to being picked by an intruder.
Still further, currently available single-point lock operators suffer from a common design disadvantage in that the escutcheons have a high profile or extend outward from the frame or wall by a substantial difference. In contrast, consumers and designers prefer a low profile operator due to the interference with the curtains, blinds or other window treatments caused by the operators having escutcheons with a higher profile. Accordingly, there is a need for a single point lock operator which provides a low profile escutcheon/handle combination that does not interfere with the operation of the window treatments.
Accordingly, there is a need for an improved cam lock or single point lock design for casement windows which provides a solution to the aforenoted problems.